Thermoelectric chip is a device designed and used to transfer heat from one side of a device to the other, with consumption of electrical energy, depending on the direction of the current. Operationally, when direct current runs through a thermoelectric chip, heat is moved from one side to the other. Therefore it can be used either for heating or for cooling. It can be applied as a cooler in electronic devices, refrigerator, drinking dispensers or air conditioners.
U.S. Pat. No. 8,001,794, issued to Robert Windisch, discloses a thermoelectric heat exchange system for fluids, in which a thermoelectric cooling module is used for cooling a fluid.
Regarding a conventional household drinking dispenser, a thermoelectric chip is generally functioning as a cooler or heater received therein. Here, when the thermoelectric chip is used for cooling, a heat sink attached on the hot side of the thermoelectric chip for dissipating heat; on the other hand, when the thermoelectric chip is used for heating, the thermal module including thermoelectric chip and heat exchanger should be adapted to function as a heat source for water heating. The temperature of water which contains in the drinking dispenser is only driven by the natural convection. Therefore, there is a significantly temperature gradient along the water container.
Beside the limitation of thermoelectric material, the thermal energy leakage from water container to the ambient environment, through thermoelectric module, further lower the efficiency of conventional thermoelectric cooler or heater. In most conventional water heaters, the thermoelectric module shuts down as the temperature is achieved to the setting point. Basically, thermoelectric module is a very good thermal conductor for thermal energy transportation. After shutting down the thermoelectric module, the thermal energy including heating energy or cooling energy in the water will be easily dissipated to the ambient environment through thermoelectric module. Thus, the thermal energy preservation effect of the container is very poor.
Conventionally, for improving the efficiency of thermoelectric module for drinking dispensers, the drinking dispensers are generally made of materials with high thermal conductivity. However, by doing so, water temperature is changing even faster. Consequently, for some commercial products, it is common to apply a small voltage on the thermoelectric chip to work as a thermal resistance when the designed water temperature is achieved in the drinking dispenser. The water temperature can be kept for a longer time. However, the additional applying voltage caused more power consumption and is not good for energy conservation.